Treatment of sausage casing for easy peeling

ABSTRACT

SAUSAGES, SUCH AS FRANKFURTERS AND BOLOGNAS, FORMED IN SYNTHETIC CASINGS ARE MORE EASILY PEELED BY SOAKING THE CASINGS, EITHER PRIOR TO OR AFTER STUFFING WITH A SAUSAGE EMULSION, WITH A SOLUBLE NON-TOXIC FOOD GRADE SALT, COMPLEX, OR COORDINATION COMPOUND OF IRON, ALUMINUM, CALCIUM OR MAGNESIUM WHICH WILL INTERACT WITH COMPONENTS OF THE SAUSAGE EMULSION TO MODIFY THE SURFACE CHARACTERISTICS OF THE SAUSAGE. THE SOLUBLE METAL COMPOUND IN SOME CASES MAY BE APPLIED TO CASINGS, E.G. FRANKFURTER CASINGS, AT THE TIME OF MANUFACTURE JUST PRIOR TO DRYING THE CASING. THE SOLUBLE METAL COMPOUNDS HOWEVER MAY BE APPLIED MORE GENERALLY TO ALL TYPES OF CASINGS EITHER JUST PRIOR TO OR AT SOME POINT AFTER THE STUFFING OF THE CASING WITH SAUSAGE EMULSION. IN THE CASE OF LARGER CASINGS OF THE TYPE USED FOR BOLOGNAS THE SOLUBLE METAL COMPOUNDS MAY BE APPLIED TO THE SOAK WATER. THESE SOLUBLE METAL COMPOUNDS MAY ALSO BE APPLIED AS AN EXTERNAL SOAK BATH FOR THE STUFFED SAUSAGES, BOTH OF THE FRANKFURTER AND BOLOGNA TYPES, OR IN THE SHOWER APPLIED TO SOAK THE CASINGS PRIOR TO PEELING, TO SATURATE THE CASING AND PROVIDE A UNIFORM APPLICATION OF THE METAL COMPOUND TO INTERACT WITH THE SAUSAGE EMULSION COMPONENTS AT THE SURFACE CONTACTING THE CASING. THE USE OF CASINGS SOAKED OR IMPREGNATED WITH THESE METAL COMPOUNDS FACILITATES REMOVAL OF THE CASING FROM THE SMOKED AND/OR COOKED SAUSAGES AT A TIME WHEN THE UNTREATED CASING COULD NOT BE PEELED FROM THE SAUSAGE.

Ill. No Drawing. Filed Sept. 22, 1969, Ser. No. 860,087 Int. Cl. A22013/00 U.S. Cl. 99-176 6 Claims ABSTRACT OF THE DISCLOSURE Sausages, suchas frankfurters and bolognas, formed in synthetic casings are moreeasily peeled by soaking the casings, either prior to or after stufiingwith a sausage emulsion, with a soluble non-toxic food grade salt,complex, or coordination compound of iron, aluminum, calcium ormagnesium which will interact with components of the sausage emulsion tomodify the surface characteristics of the sausage. The soluble metalcompound in some cases may be applied to casings, e.g. frankfurtercasings, at the time of manufacture just prior to drying the casing. Thesoluble metal compounds however may be applied more generally to alltypes of casings either just prior to or at some point after thestufiing of the casing with sausage emulsion. In the case of largercasings of the type used for bolognas the soluble metal compounds may beapplied to the soak water. These soluble metal compounds may also beapplied as an external soak bath for the stuffed sausages, both of thefiankfurter and bologna types, or in the shower applied to soak thecasings prior to peeling, to saturate the casing and provide a uniformapplication of the metal compound to interact with the sausage emulsioncomponents at the surface contacting the casing. The use of casingssoaked or impregnated with these metal compounds facilitates removal ofthe casing from the smoked and/ or cooked sausages at a time when theuntreated casing could not be peeled from the sausage.

BACKGROUND OF THE INVENTION Field of the invention In the preparation ofsausages of various types, ranging from smaller sausages such asfrankfurters and viennas up to large sausages such as bolognas, thesausage meat is normally extruded into a tubular casing for processing.In the early days of the packing industry, sausages were prepared usingnatural casings. About forty years ago, casings were developed ofregenerated cellulose which have been used in the preparation ofsausages of all sizes. Clear, thin-walled, cellulosic casings were usedprimarily in the preparation of frankfurters and viennas. Largerdiameter, heavy-walled, cellulosic casings, both clear andfibrous-reinforced, were used in the manufacture of larger sausages ofthe bologna type. In the manufacture of both large and small sausages, amajor problem has been the shipping of the sausage casing from thesausage after it has been smoked and cooked by the meat packer. Thisproblem has been especially great in the case of frankfurter sausagesbecause of the large number of sausages processed.

in the preparation of frankfurters and other small sausages, a sausagepaste or emulsion is extruded from a stulfing horn into a shirredsausage casing. The shirred casing will normally contain from 80 to 160feet of casing in a shirred length of 10 to inches. The sausage paste oremulsion is extruded into the casing at a high speed with the resultthat the entire length of the casing is filled with sausage emulsion ina few seconds. As the casing is filled with sausage emulsion it passesinto a linking device which F we twists the casing to form individualsausage links. The encased lengths of sausage are then cooked and smokedand are stored in a refrigerated room for about 24 hours prior topeeling. After extended storage in the chill room the encased sausagesare removed into a peeling room which is maintained at a relatively highhumidity. The chilled sausage has a considerable amount of moisturecondensed on its surface after removal from the chill room whichfacilitates removal of the casing from the individual sausages. Thesausages are passed through a commercial peeling machine which cuts openthe casing without cutting the encased meat and removes the casing fromthe sausage. Sausages which are not separated from the casing by theautomatic peeling machinery must be separated by hand which adds to thecost of processing. Normally, if a particular string of sausage isdiflicult to peel it is returned to the chill room and cooled for anadditional period of time to allow the meat emulsion to set up morethoroughly and facilitate casing removal. In the processing offrankfurters and other small sausages a major item of cost is theremoval of easing from the finished sausages, particularly the cost of ahigh inventory in the chill room and the cost of hand peeling sausageswhich do not peel cleanly on the automatic peeling machinery.

Description of the prior art The prior art has been concerned with theproblem of improving the peelability of synthetic casings from sausagesfor many years. The attempted solutions to the problem suggested by theprior art have mainly involved the application of various coatings tothe inner surface of the synthetic casings to permit the casings to bepeeled more readily from the sausages. Weingand U.S. Pat. No. 2,709,138discloses an internal release coating of a fatty isocyanate. Firth U.S.Pat. No. 3,106,471 discloses release coatings of fatty ketenes.Underwood U.S. Pat. No. 2,901,358 discloses release coatings of stearatochromic chloride chemically combined on the inner surface of the casing.Chiu U.S. Pat. No. 3,307,956 discloses release coatings of Water solublesilicones. Turbak U.S. Pat. No. 3,442,663 discloses release coatings ofwater insoluble polymerized silicones applied internally as apolymerized methyl hydrogen siloxane. Bridgeford U.S. Pat. No. 3,451,-827 discloses release coatings of lactic acid, calcium lactate,trisodium hexametaphosphate, aluminum sulfate, potassium aluminumsulfate, lecithin diammonium phosphate, carboxymethyl cellulose,silicone oil, calcium phytate, inositol, glycerophosphoric acid,acetylated monoglycerides, methyl cellulose, or cetyl alcohol appliedinternally to the casing during the mechanical shirring of the casing.

The prior art, as exemplified by the aforementioned patents, has hadonly limited success in providing easily peelable synthetic casings forfrankfurters and other small size sausages. The various coatingsdisclosed in the prior art are applied to the interior of large sizecasings, such as those used for bolognas, etc., by an internal slugcoating technique. This coating technique however is not applicable tothe interior coating of frankfurter type synthetic sausage casingsbecause of the very small diameter of such casings and the speed ofmanufacture which makes it diflicult to introduce a coating liquidinside the casing. Coating materials such as those disclosed in =Pat.3,307,956 may be added from the outside of the casing in aqueoussolution. However, the silicone coating materials which are watersoluble in aqueous alkali are not approved coating materials, for usewith meat or other food products. Coating materials of the typedisclosed in U.S. Pats. 3,442,663 and 3,451,827 may be applied to smalldiameter casings during mechanical shirring on a shirring machine. Theapplication of coatings during shirring however is somewhat irregularand often results in an interior coating which is incomplete in coverageand quite variable in thickness.

SUMMARY OF THE INVENTION This invention is based upon the discovery thatartificial sausage casings, particularly casings of regeneratedcellulose, both of the clear cellulose and fibrous-reinforced types, maybe more easily peeled from sausages processed in the casing whenthoroughly impregnated or soaked with solutions of salts, chelates, orcomplexes of iron, aluminnm, calcium, or magnesium which interact withcomponents of a sausage paste or emulsion to modify the surfaceproperties of the sausage and to permit easy release of the casing. Thecompounds mentioned above may be applied to frankfurter type casingsafter completion of all chemical processing and washing and just priorto drying of the casing. Where the compounds are added to frankfurtercasings during manufacture, these compounds are added in aqueoussolution at a pH greater than 4 so that the casing is not damaged onextended storage. The compounds used in treating the casing arenon-toxic edible materials which remain soluble after the casing hasbeen dried and shirred. The materials which are saturated in andimpregnated throughout the casing are extractable from the casing intothe outer surface layer of the sausage paste or emulsion processed inthe casing. Under these conditions the impregnated materials interactwith proteinaceous or fatty or other components of the sausage emulsionor paste to modify the surface properties of the sausage and permit easypeeling of the casing from the sausage. The impregnation of metal saltsinto casing during manufacture is more or less limited to frankfurtertype casings. The process of this invention, however, is one which isgenerally applicable to frankfurter casings and to larger sausagecasings of the type used in the processing of bolognas and other largersausages. In applying this invention to provide easy release of bothsmall and large clear cellulosic casings or fibrous casings, the solublemetal compounds used to impregnate the casings are applied to the casingin the soak water used to soften the casing prior to stuffing with thesausage paste or emulsion or the stuffed sausage may be soaked for ashort time in a solution of the metal compounds to provide a sufficientamount of the metal compounds at the surface of the casing to interactwith the sausage emulsion or paste components and provide for easyrelease of the casing. Similarly, solutions of the metal compounds maybe applied to encased frankfurters after stuffing and linking to soakthe casings with the metal compounds in an amount suflicient to interactwith components of the sausage paste or emulsion to provide for easypeeling of the casing therefrom. The solutions of the metal compoundsmay also be used in the shower applied to stufied and linked frankfurtercasings to facilitate peeling the casing from the frankfurters.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the manufacture ofregenerated cellulose sausage casings, viscose is extruded through anannular die into a coagulating and regenerating bath to produce a tubeof regenerated cellulose. The tube is subsequently Washed, plasticizedwith glycerin, and dried while inflated. under a substantial airpressure for size control. After drying, the casing is wound on reelsand subsequently shirred on high speed shirring machines, such as thosedescribed in US. Pats. 2,010,626; 2,583,654; 2,722,714; 2,722,715;2,723,201; etc. Reinforced cellulose casing, also known as fibrouscasing, is prepared by forming a tube of a long fiber hemp paper, or thelike, impregnating the paper tube with viscose, and regeneratingcellulose in and on the paper tube. The viscose-impregnated tube ispassed into a coagulating and regenerating bath and then subsequentlywashed, plasticized with glycerin and dried under air pressure. Fibrouscasing is used largely for the production of large sausages such asbolognas. Large diameter clear unreinforced regenerated cellulose casingis also used in the production of large bologna type sausages. Fibrouscasing and the large clear cellulosic casings are normally sold as flatstock either in the form of reel stock or cut into pieces ofpredetermined length.

We have found that cellulosic casings, and other synthetic sausagecasings are more easily peeled from sausages processed therein ifthoroughly soaked with edible non-toxic salts, chelates, or coordinationcomplexes of iron, aluminum, calcium, or magnesium. In the case of smalldiameter clear cellulosic casings of the type used in the production offrankfurter sausages, the soluble metal salts, chelates, or coordinationcomplexes, are applied to the casing either in the glycerin bath or in aseparate bath following the glycerin bath just prior to drying. Thesoluble metal compounds can also be applied to soak baths for largerdiameter clear and fibrous casings or can be applied to soak baths forsausages encased in the casings, Whether of the large or small size. Thesoluble metal compounds can also be applied to small sausages in theform of a shower of the solution applied to the encased sausages as asubstitute for the acid shower which is often used in the processing offrankfurter sausages.

In carrying out this invention any soluble non-toxic edible salts,chelates, or coordination complexes of iron, aluminum, calcium ormagnesium may be used which will interact with the components of thesausage emulsion to modify the surface characteristics of the sausage atthe interface between the sausage and the casing. Typical compoundswhich may be used include sulfates, citrates, malates, tartrates,gluconates, ascorbates, erythorbates, chlorides, nitrates, etc. ofaluminum, iron, calcium or magnesium, either in the form of the watersoluble salts buffered to a pH at which the metal iron remains insolution or in the form of mixed salts such as ferric ammonium sulfateor ferric ammonium citrate, or chelated or complexed with u-hydroxyaliphatic carboxylic acids or u-amino aliphatic carboxylic acids orsalts thereof or polyfunctional acids such as EDTA. When solutions ofthese compounds are applied to frankfurter type casings duringmanufacture of the casings the solutions must be buffered to a pHgreater than about 4 to prevent acidic degradation of the casing. Whenthe solutions are used in treating casings immediately prior to stuflingwith sausages or for treating encased sausages, in accordance with theprocess of this invention, it is possible to use substantially moreacidic solutions. In either case, the metal compounds are present in thesolution in a concentration sufiicient to provide more than about 50p.p.m. of soluble metal in the casing.

In demonstrating the eflicacy of this invention, casings treated inaccordance with the invention are compared with untreated controls. Inthe preparation of frankfurter sausages, the stuffed casings are soakedin a solution of one of the aforementioned metal compounds aftercooking. The sausages may be soaked prior to smoking and chilling, ormay be soaked by means of a shower following the chilling operation. Inany event, the stuffed casings are chilled for extended periods inaccordance with standard commercial practice prior to peeling. The easeof peeling of the treated casings from the sausages encased therein iscompared with the ease of peeling of untreated control casings.

In the case of bologna sausages, the soluble metal compounds used totreat the casings are preferably added to the soak water used to makethe casings flexible in preparation for stuffing. The casings arestuffed with the usual bologna paste or emulsion and given a normalcooking and smoking. Alternatively, the bologna paste or emulsion may bestuffed in an untreated casing and the stuffed sausage soaked briefly ina solution of one of the afore mentioned metal compounds to facilitateremoval of the casing from the sausage. The ease of peeling of thetreated casings from the sausages encased therein is then compared withthe ease of peeling of untreated control casings.

As will be noted in the following examples, the treated casingsinvariably are peeled more readily using standard commercial peelingequipment than are the untreated controls. In cases where hand peelingof the casing is used the treated casings peel more readily and do notpull ofi meat from the outside of the sausage as is the case withuntreated control casings.

The following non-limiting examples are illustrative of the scope ofthis invention:

Example 1 A solution is prepared by dissolving 2300 g. ferric ammoniumcitrate and 2710 g. aluminum sulfate in gal. distilled water. To thissolution there is added 2600* g. of 23% aqueous sodium hydroxide toadjust the pH to a value greater than 4. To this solution there is added1000 g. trisodium citrate to complex the partially basic ferric ammoniumcitrate and thus stabilize the solution. The solution as prepared isready for treatment of frankfurters in accordance with this invention.

Casings are treated in accordance with this invention as part of astandard commercial frankfurter manufacturing process. Clear cellulosefrankfurter casings in shirred form, are stuffed with a frankfurterpaste or emul= sion on a commercial stufiing machine. The normalstufiing operation is such that the shirred casing is stulfed out from ashirred length of the order of l0-20 inches out to an extended length of80-160 feet in the matter of a few seconds. As the casing is beingstuffed it passes through a commercial linking machine to form a stringof frankfurter links.

The string of frankfurter links is passed through the treating solutionprepared above to soak the casings on the frankfurter and provide aconcentration of at least 50 ppm. metal in the casing. The metalcompound saturated in the wall of the casing is soluble and capable ofinteracting with components of the frankfurter emulsion to modify thesurface characteristics of the sausage and facilitate removal of thecasing. Part of the frankfurter links are by-passed around the treatingbath to provide a control for comparison with the treated casings. Thestring of frankfurter links, both treated and untreated is then placedin a chill room for a period of 2448 hours or longer if needed. Thethoroughly chilled sausages are then brought into a highly humid room'where moisture condenses on the casing to facilitate casing removal.The chilled, sweated frankfurter links are then passed through acommercial peeling machine which removes casing from the individuallinks.

As an extreme test of the efiicacy of this invention, some of thecontrols and treated casings, stuffed with frankfurter emulsion, areremoved from the chill room after about 2- /2 hours to evaluate thepeeling of casing under these conditions. The control casing can not bepeeled from frankfurters using commercial peeling equipment and, infact, attempts to peel the casing manually result in tearing meat fromthe surface of the frankfurters. The treated frankfurter casings, i.e.frankfurters passed through the treating solution, peel very well fromthe frankfurters using standard commercial machinery with very fewpeeling misses. Furthermore, the sausages missed on the peeling machinecan be peeled by hand without pulling meat from the surface of thefrankfurters.

When frankfurters formed in control casings and treated frankfurters arerefrigerated for the full 24-48 hour period there is a substantialimprovement in the performance of the untreated controls. Nevertheless,the treated casings are peeled with substantially fewer misses evenunder these conditions. It is thus seen that the use of the treatingsolution improves substantially the peeling performance under normalprocessing conditions and further permits the peeling of casing from thefrankfurters after a much shorter chill period. The use of the treatingsolution on the stuffed frankfurters permits the meat packer to maintaina lesser inventory in the chill room and/or a substantial increase inthroughput as a result of the improved peelability of casing after ashort chill period.

Example 2 A treating solution is prepared by dissolving 1800 g. ferricsulfate in about 5 gal. distilled water together with 1800 g. trisodiumcitrate and 3050 g. citric acid to form a soluble chelate. There is thenadded to the solution 3800 g. of 28% aqueous ammonia to bring the pH ofthe solution to 7.2 and form a stable treating solution. This treatingsolution is used in the treatment of frankfurter sausages during aconventional frankfurter manufacturing process as previously described.

Frankfurters are prepared and processed in this example using theconditions described in Example 1. A string of frankfurter links ispassed through the treating solution and subsequently smoked and cooked,chilled and peeled. Some strings of frankfurter sausages are sentdirectly to cooking and smoking without passing through the treatingsolution. These are the untreated controls. After 2 /2 hours in thechill room, the treated casings can be readily removed from thefrankfurters using commercial fast peeling machinery while the untreatedcontrols can not be removed. After a full 24-48 hour chill period thetreated casings generally exhibit substantial improvement in peeling ascompared to untreated controls.

Example 3 A solution is prepared by dissolving 1800 g. ferric sulfate inabout 5 gal. distilled water together with 2500 g. malic acid to form asoluble complex or chelate. The solution is neutralized to pH 6.9 byaddition of 2200 g. of 28% aqueous ammonia and 1900 g. of 23% NaOH.

The treating solution prepared above is used in soaking fibrous casingin preparation for the manufacture of bolognas. This solution is used inplace of the usual presoak for softening the casing in preparation forstuffing. The soaked casing is then used in a conventional process formanufacture of bologna sausages.

Treated casings, together with untreated control casings (i.e. casingssoaked in plain water) are used in the preparation of bologna sausages.The casings are stuffed with bologna paste or emulsion and aresubsequently cooked and smoked. Eventually, the casing is peeled fromthe bolognas prior to slicing the sausage in preparation for packagingand marketing. The untreated control casings stick to the surface of thesausage and tend to tear portions of meat from the surface. The treatedcasings peel readily from the sausage without tearing away meat.

Example 4 A treating solution is prepared by dissolving 2400 g. ferricsulfate in about 5 gal. distilled water together with 2400 g. citricacid to form a soluble complex or chelate. The solution is neutralizedto pH 6.5 by addition of 2300 g. of 28% aqueous ammonia and 2500 g. of23% aqueous NaOH.

The treating solution is used in the treatment of stuffed and linkedfrankfurters substantially as described in Examples 1 and 2. The treatedcasings, together with untreated controls, are evaluated by peelingusing commercial peeling machines after various intervals in the chillroom following the cooking and smoking. The treated casings peelsubstantially better than untreated casings after a 2 /2 hour chillperiod. After the full 24-48 hours chill period the treated casing stillpeels substantially better when the frankfurters are peeled oncommercial fast peeling machines.

Example 5 A treating solution is prepared comprising 10% ferric sulfate,15% malic acid and 5% ammonia in 5 gal. distilled water. The malic acidforms a soluble complex or chelate to prevent precipitation and theammonia neutralizes the solution to about pH 7.0.

This treating solution is used in the preparation of frankfurters asdescribed in Examples 1 and 2, except that the solution is applied tothe stuffed and linked frankfurters in a conventional shower operationrather than by dipping in a treating bath. From the shower operation thefrankfurters are passed to the smoking and cooking operation andsubsequently to the chill room.

The treated casings are more easily removed from frankfurters than areuntreated control casings both after a short chill period and after afull 24-48 hours chill period. After the short chill period, the treatedfrankfurters exhibit an extremely small proportion of peeling missesusing commercial fast peeling machinery. After the short chill period itis virtually impossible to remove untreated control casings usingstandard fast peeling machinery.

Example 6 A treating solution is prepared by dissolving 1300 g. ferricsulfate and 2300 g. aluminum sulfate in about gal. distilled Watertogether with 60 g. trisodium citrate and 1000 g. malic acid to formstable coordination complexes. The solution is neutralized to pH 5.7 byaddition of 1800 g. 28% aqueous ammonia and 1500 g. 23% aqueous NaOH.

This treating solution is used in the treatment of stuffed and linkedfrankfurters substantially as described in Examples 1 and 2. The treatedcasings, together with untreated controls, are evaluated by peelingusing commercial peeling machines after various intervals in the chillroom following the cooking and smoking. The treated casings peelsubstantially better than untreated casings after a 2 /2 hour chillperiod. After the full 2448 hours chill period the treated casing stillpeels substantially better when the frankfurters are peeled oncommercial fast-peeling machines.

Example 7 A treating solution is prepared by dissolving 1800 g. ferricsulfate and 1200 g. aluminum sulfate in about 5 gal. distilled watertogether with 1800 g. trisodium citrate and 100 g. citric acid to formstable complexes or chelates. The solution is neutralized to pH 7 byaddition of 1000 g. 28% aqueous ammonia.

This treating solution is used to treat stuffed and linked frankfurterssubstantially as described in Examples 1 and 2. Treated casings peelsubstantially better than untreated casings after a 2 /3: hour chillperiod or after a full 24-48 hours chill period on commercialfast-peeling machines.

Example 8 A casing treating solution is prepared by dissolving 4800 g.ferric sulfate in about 5 gal. distilled water together with 3200 g.trisodium citrate and 3300 g. malic acid to form soluble complexes orchelates. The solution is then neutralized to pH 7 by addition of 4950g. 38% aqueous ammonia.

This treating solution is used in the preparation of bologna sausages asdescribed in Example 3. The casings are stuffed with bologna paste oremulsion and are subsequently cooked and smoked. Eventually, the casingis peeled from the bolognas prior to slicing in preparing for packagingand marketing. The untreated control casings stick to the surface of thesausage and tend to tear portions of the meat from the surface. Treatedcasings peel readily from the sausage without tearing away the meat.

Example 9 A casing treating solution is prepared by dissolving 2400 g.fern'c sulfate and 1600 g. ferric ammonium citrate in about 5 gal.distilled water together with 1100 g. malic acid to form a stablesoluble complex or chelate. The solution is neutralized to pH 7 byaddition of 2500 g. 28% aqueous ammonia.

The treating solution is used in the treatment of frankfurters asdescribed in Example 5. The solution is ap plied during the conventionalshower operation rather than by a separate dip. The treated casings aremore easily removed from the frankfurters than are untreated controls,both after a short chill period and after a full 24-48 hour chillperiod.

Example 10 A casing treating solution is prepared by dissolving 2200 g.calcium chloride dihydrate in about 5 gal. distilled water. The solutionis buffered to pH 7 by addition of lime or hydrochloric acid, asrequired.

This calcium chloride treating solution is used in the treatment ofstuffed and linked frankfurters substantially as described in Examples 1and 2. The treated casings peel substantially better than untreatedcontrol casings both after a 2 /2 hour chill period and a 24-48 hourchill period.

Example 11 A casing treating solution is prepared by dissolving 600 g.ferric sulfate and 800 g. calcium chloride dihydrate in about 5 gal.distilled water together with 800 g. malic acid to complex the ferricsulfate. The solution is neutralized to pH 6.7 by addition of 800 g. 28%aqueous ammonia.

This treating solution is used in the treatment of stuffed and linkedfrankfurters as described in Example 5. The solution is applied in aconventional shower operation rather than in a separate treating bath.The treated casings are more easily removed from the frankfurters thanare untreated control casings, both after a short chill period and aftera full 2448 hour chill period.

Example 12 A casing treating solution is prepared by dissolving 1590 g.magnesium chloride hexahydrate in about 5 gal. water and buffering thesolution to pH 7.

The treating solution is used in the treatment of stulfed and linkedfrankfurters substantially as described in Examples 1 and 2. The treatedcasings, together with untreated controls, are evaluated by peelingusing commercial peeling machines after various intervals in the chillroom following the cooking and smoking. The treated casings peelsubstantially better than untreated control casings both after a 2 /2hour chill period and after a full 24-28 hour chill period.

Example 13 A casing treating solution is prepared by dissolving calciumnitrate in about 5 gal. distilled water at a concentration of about 10%.

This treating solution is used in the treatment of stuffed and linkedfrankfurters substantially as described in Examples 1 and 2. The treatedcasings peel substantially better than untreated control casings bothafter a short 2 /2 hour chill period and after the full 24-48 hour chillperiod.

Example 14 A casing treating solution is prepared by dissolving aluminumsulfate in distilled water and complexing with trisodium citrate.Sufiicient aqueous NaOH is then added to render the solution aboutbasic.

The treating solution is used in the treatment of frankfurterssubstantially as described in Examples 1 and 2. The treated casings peelsubstantially better than untreated control casings both after a short 2/2 hour chill period and after the full 24-48 hour chill period.

Example 15 A casing treating solution is prepared by dissolvingmagnesium nitrate in about 5 gal. distilled water at a concentration ofabout 20%.

This treating solution is used in the preparation of frankfurterssubstantially as described in Examples 1 and 2. The treated casings peelsubstantially better than untreated control casings both after a short 2/2 hour chill period and after a full 24-18 hour chill period.

From the foregoing examples we have demonstrated that the saturation andimpregnation of synthetic sausage casings with salts, chelates, orcoordination complexes of iron, aluminum, magnesium or calcium isgenerally effective to provide improved peeling of the casing fromfrankfurters and similar sausages. The treatment may be applied to thecasing prior to stuffing or to the stufied sausage. While the processhas been described as applied to cellulosic casings it should beunderstood that the compounds mentioned may be applied to any syntheticsausage casings such as casings of collagen, alginates, starch, dextran,polyvinyl alcohol, etc., where improved peelability of the casing isdesired.

Without limiting ourselves to any particular theory of operation of theinvention, we believe that the compounds used in the treating solutionmay function to tan, harden, or denature proteinaceous components of thesausage emulsion or may interact with fatty components to provide soaplike derivatives which improve the peelability or releasecharacteristics of the casing at the point of contact with the sausageencased therein. The compounds which are used in the treating solutionmust be soluble in water or in the sausage emulsion under conditions ofuse so that they are mobile or readily leached or absorbed from thecasing into or onto the surface of the sausage to interact with thesurface layer or skin of the sausage on contact therewith to provide theimproved release properties. The compounds in the treating solution areuniformly impregnated or saturated throughout the casing and are easilyapplied from outside the casing, thus making possible the easy peelingof the casing. Casings treated in accordance with this invention notonly provide improved peelability but also permit the peeling ofsausages at an earlier point in the processing, thus increasing theover-all rate of processing of the sausages through the meat packingplant.

We claim:

1. A process for treating an artificial sausage casing to improve thepeelability of the casing from a sausage stuifed and processed thereincomprising impregnating said casing after drying but prior to stufiingor impregnating said casing on a sausage after stufiing with a solutionof a non-toxic edible sulfate, citrate, malate, tartrate, gluconate,ascorbate, erythorbate, chloride or nitrate of calcium or magnesium; ora salt of iron or aluminum complexed or chelated with an rx-hydroxyaliphatic carboxylic acid or a salt thereof, or an tit-amino aliphaticcarboxylic acid or a salt thereof, or ethylene diamine tetraacetic acid,capable of interacting with one or more components of the sausage tomodify the surface of the sausage in contact with the casing.

2. A process as defined in claim 1 in which the salt, chelate, orcoordination complex is present in a concentration suificient to providea concentration of metal in the casing of at least ppm.

3. A process as defined in claim 1 in which said solution is of a saltof iron or aluminum complexed with an Cthydroxy aliphatic carboxylicacid or a-amino aliphatic canboxylic acid or a salt thereof and bufferedto a pH greater than 4.

4. A process as defined in claim 3 in which the iron or aluminum salt iscomplexed with citric or malic acid or a salt thereof and neutralizedwith aqueous ammonia or caustic to a pH greater than 4.

5. A process as defined in claim 1 in which said casing is soaked insaid treating solution prior to stuffing.

6. -A process as defined in claim 1 in which said casing is stuffed withsausage paste or emulsion and then soaked in or showered with saidtreating solution prior to cooking, smoking, and/or chilling.

References Cited UNITED STATES PATENTS 3,262,789 7/1966 Broumand 99-171CA 2,167,105 7/1939 Drew 117-144 2,306,278 12/1942 Reichel 117-1443,307,956 3/1967 Chiu 99-175 UX 2,813,034 11/1957 Weingand 99-1763,451,827 6/1969 Bridgeford 99-176 3,533,808 10/1970 Cameron 99-176FRANK W. LUTTER, Primary Examiner R. HALPER, Assistant Examiner U.S. Cl.X.R.

